#include "constraints.h"
#include "asn_internal.h"

int asn_generic_no_constraint(asn_TYPE_descriptor_t *type_descriptor,
                              const void *struct_ptr,
                              asn_app_constraint_failed_f *cb, void *key) {
  (void)type_descriptor; /* Unused argument */
  (void)struct_ptr;      /* Unused argument */
  (void)cb;              /* Unused argument */
  (void)key;             /* Unused argument */

  /* Nothing to check */
  return 0;
}

int asn_generic_unknown_constraint(asn_TYPE_descriptor_t *type_descriptor,
                                   const void *struct_ptr,
                                   asn_app_constraint_failed_f *cb, void *key) {
  (void)type_descriptor; /* Unused argument */
  (void)struct_ptr;      /* Unused argument */
  (void)cb;              /* Unused argument */
  (void)key;             /* Unused argument */

  /* Unknown how to check */
  return 0;
}

struct errbufDesc {
  asn_TYPE_descriptor_t *failed_type;
  const void *failed_struct_ptr;
  char *errbuf;
  size_t errlen;
};

static void _asn_i_ctfailcb(void *key, asn_TYPE_descriptor_t *td,
                            const void *sptr, const char *fmt, ...) {
  struct errbufDesc *arg = key;
  va_list ap;
  ssize_t vlen;
  ssize_t maxlen;

  arg->failed_type = td;
  arg->failed_struct_ptr = sptr;

  maxlen = arg->errlen;
  if (maxlen <= 0) return;

  va_start(ap, fmt);
  vlen = vsnprintf(arg->errbuf, maxlen, fmt, ap);
  va_end(ap);
  if (vlen >= maxlen) {
    arg->errbuf[maxlen - 1] = '\0'; /* Ensuring libc correctness */
    arg->errlen = maxlen - 1;       /* Not counting termination */
    return;
  } else if (vlen >= 0) {
    arg->errbuf[vlen] = '\0'; /* Ensuring libc correctness */
    arg->errlen = vlen;       /* Not counting termination */
  } else {
    /*
     * The libc on this system is broken.
     */
    vlen = sizeof("<broken vsnprintf>") - 1;
    maxlen--;
    arg->errlen = vlen < maxlen ? vlen : maxlen;
    memcpy(arg->errbuf, "<broken vsnprintf>", arg->errlen);
    arg->errbuf[arg->errlen] = 0;
  }

  return;
}

int asn_check_constraints(asn_TYPE_descriptor_t *type_descriptor,
                          const void *struct_ptr, char *errbuf,
                          size_t *errlen) {
  struct errbufDesc arg;
  int ret;

  arg.failed_type = 0;
  arg.failed_struct_ptr = 0;
  arg.errbuf = errbuf;
  arg.errlen = errlen ? *errlen : 0;

  ret = type_descriptor->check_constraints(type_descriptor, struct_ptr,
                                           _asn_i_ctfailcb, &arg);
  if (ret == -1 && errlen) *errlen = arg.errlen;

  return ret;
}
